Earth's Three Main Layers

Earth's Three Main Layers

• The Earth's rocky layers consist of the crust, mantle, and core
• These layers are similar to those found on other rocky planets
• The core is composed of an inner solid iron core and an outer molten iron core
• The core is denser than the mantle and crust

Crust

• The outermost layer of the Earth
• It’s where life exists
• Thin layer, averaging about 20 miles thick
• Thinner under oceans (about 3 miles)
• Thicker under mountains
• Composed of rocks, minerals, and metals
• The crust is broken into multiple tectonic plates that move
• These moving plates cause earthquakes, volcanoes, and mountains
• The lithosphere is a section of the crust and upper mantle that is constantly moving

Mantle

• The layer between the crust and core, making up 84% of the Earth's volume
• Semi-solid layer, with flowing molten iron, magnesium, and silicon
• Extends from about 20 to 1800 miles below the surface
• Consists of layers like the asthenosphere, central mantle (transition zone), and lower mantle
• The asthenosphere (upper mantle) is semi-molten and moves in convection currents influencing tectonic plates movement.
• The central mantle (transition zone) has denser rocks and significant water content (hydroxide)
• The lower mantle is the hottest and densest part of the mantle, largely solid.

Core

• Located at the center of the Earth
• Consists of two layers: inner and outer core
• The inner core is a solid ball of extremely hot and high-pressure metal (mostly iron and nickel)
• The outer core is a liquid of iron and nickel, slightly less pressure and temperature than the inner core
• Movement within the outer core generates Earth's magnetic field
• Begins approximately 1800 miles below the surface and continues to the core's center, more than 2,000 miles below the surface.